Datasheet TPS2410, TPS2411 (Texas Instruments) - 8

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TPS2410 TPS2411
SLVS727C – NOVEMBER 2006 – REVISED JUNE 2009 ..
www.ti.com RSET:
A resistor connected from this pin to GND sets the MOSFET fast turn-off comparator threshold. The threshold is slightly positive when the RSET pin is left open. Current drawn by the resistor programs the turn-off voltage to increasing negative values. The TPS2411 must have a negative threshold programmed to avoid an unstable condition at light load. The expression for R(RSET) in terms of the fast comparator-trip voltage, V(OFF), follows. æ ö -470.02 R = ç ÷ (RSET) ç V - 0.00314 ÷ è (OFF) ø (1) The units of the numerator are (V × V/A). V(OFF) is positive for V(A) greater than V(C), V(OFF) is less than 3 mV, and R(RSET) is in ohms.
RSVD:
Connect to ground.
STAT:
STAT is a multifunction pin. STAT outputs the status of the GATE pin drive. The internal weak pull-up pulls STAT to VDD when GATE is being driven high and V(GATE) is 0.4 V greater than V(A). If STAT is externally pulled below VDD/2 while the pin would otherwise be high, the turnoff threshold is shifted negative (~157 mV) from the RSET programmed value. Interconnecting the STAT pins of redundant devices, in systems that normally have both devices on, reduces the likelihood that both devices will turn off in the event of a transient. See the FUNCTIONAL BLOCK DIAGRAM, INPUT ORing and STAT, and Figure 13.
UV, OV, PG:
These signals are used to monitor an input voltage for proper range. PG sinks current to GND if UV is below its threshold, OV is above its threshold, or VDD is below the internal UVLO. PG may not be valid when VDD is below the UVLO. A high input on OV causes GATE to be driven low. UV does not effect the MOSFET operation. This permits OV to be used as an active-high disable. OV and UV should be connected to ground when not used, and PG may be left open. Multiple PG pins to be wire ORed using a common pull-up resistor.
VDD:
VDD is the primary supply for the gate drive charge pump and other internal circuits. This pin must be connected a source that is 3 V or greater when the external MOSFET is to be turned on. VDD may be greater or lower than the controlled bus voltage. A 0.01-µF bypass capacitor, or 10-Ω and a 0.0 1-µF filter, is recommended because charge pump currents are drawn through VDD. 8 Submit Documentation Feedback Copyright © 2006–2009, Texas Instruments Incorporated Product Folder Link(s): TPS2410 TPS2411 Document Outline FEATURES APPLICATIONS DESCRIPTION ABSOLUTE MAXIMUM RATINGS DISSIPATION RATINGS RECOMMENDED OPERATING CONDITIONS ELECTRICAL CHARACTERISTICS: TPS2410/11 DETAILED DESCRIPTION TYPICAL CHARACTERISTICS APPLICATION INFORMATION OVERVIEW TPS2410 vs TPS2411 – MOSFET CONTROL METHODS N+1 POWER SUPPLY – TYPICAL CONNECTION INPUT ORing – TYPICAL CONNECTION SYSTEM DESIGN AND BEHAVIOR WITH TRANSIENTS RECOMMENDED OPERATING RANGE TPS2410 REGULATION-LOOP STABILITY MOSFET SELECTION AND R(RSET) GATE DRIVE, CHARGE PUMP AND C(BYP) FAST COMPARATOR INPUT FILTERING – C(FLTR) UV, OV, AND PG VDD, BYP, and POWERING OPTIONS INPUT ORing AND STAT BIDIRECTIONAL BLOCKING AND PROTECTION OF C ORing EXAMPLES SUMMARIZED DESIGN PROCEDURE Layout Considerations